<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>

  <div>hello1</div>
  <div>hello2</div>
  <div>hello3</div>
  <div>hello4</div>

  <script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
  <script>
    var arr = [1, 3, 5, 6, 8]
    // each
    $.each(arr, function (key, value) {
      console.log(key, value);
    })

    // toArray 将jQuery对象转成数组
    var arr = $('div').toArray()
    console.log('toArray', arr)

    // type 得到数据类型
    console.log($.type($));
    
  </script>
</body>
</html>